A succession of long rallies left Williams grunting, stumbling, lunging, squealing, flailing her arms and scolding herself.

Despite all the drama and trauma, she moved one round closer to a record seventh Key Biscayne title.

Williams is playing in her first tournament after a month-long layoff, and rustiness may explain her 41 unforced errors, including seven double-faults. And the 20-year-old Garcia kept Williams on her heels with deep groundstrokes and serves that topped out at 117 mph.

"I can play a hundred times better," Williams said. "I really gave myself a tremendous amount of trouble out there. Granted she played great, but I made so many errors ... 40-something errors. It's not the way to play professional tennis. Maybe amateur."

Some of their side-to-side baseline exchanges had the stadium crowd roaring, and Williams needed 2½ hours to complete the victory. But she finished in a hurry, serving out the final game at love with the help of consecutive aces.

Ranked No. 1, Williams is playing for the 14th time at Key Biscayne, an hour from her home in Palm Beach Gardens. She won the event for the first time in 2002 and tied Andre Agassi's record of six titles last year.

"It's always nice to play against a big player," Garcia said. "You are working and practicing to play this match, because it's in this kind of match you can learn more. But next time I prefer to win."